It's a good question, and somewhat hard to disentangle. My view is that there's a strong opinion from techies that "the tubes" should be a commodity/utility service, and therefore there's resistance to various kinds of provider control/segmentation of uses. Basically, this view holds that pipes should be treated as utility or common-carrier type provisioning.
Having that kind of view does correlate with being a heavier user, but I think also has an independent basis in technical/political ideals of what the internet should be, i.e. the correlation is due to a common underlying cause. I think it's probably not strong enough to dissuade that activity through market forces, though, because the percentage of users who have that technical knowledge and those technical ideals is quite small.
I'm one example, I think: I'm wary of both tethering charges and of some content providers' attempts to market-segment iPad content, and I own neither a smartphone nor an iPad, so it's not really based on saving me money.
(Offtopic edit: Huh, are you the same 'gojomo' from Bitzi? If so, I'm the 'delirium' that contributed some code to the Bitzi Bitcollider something like 10 years ago, to extract video metadata. Thought that handle sounded familiar.)